Analytical & Bioanalytical Electrochemistry
Volume:16 Issue: 3, Mar 2024

Sodium hypochlorite (NaClO) is used on a large scale for water disinfection, fabric bleaching, and odor removal. It is preferred due to the environmental risk of liquid chlorine associated with storage and transport. The objective of the research was the electrochemical generation of sodium hypochlorite from an aqueous solution of sodium chloride. Different operating conditions affecting the sodium hypochlorite generation process were studied, including electrical potential (6 and 10 V), sodium chloride concentration (80 and 120 g/L), and electrolysis time (30 and 60 minutes. To analyze the effect of the factors with respect to the response variable such as sodium hypochlorite concentration and energy consumption per kilogram of hypochlorite produced, a two-level factorial design was used for each factor. The best operating conditions produced when the applied electric potential was 10 V, sodium chloride concentration 120 g/L, and treatment time of 60 minutes reaching a concentration of 2276 g/L NaClO and a free chlorine percentage of 0.23 %. As well, the energy consumption per kilogram of hypochlorite is in the range of 3.31 and 11.78 kWh/kg.

The inhibiting impact of Mentha piperita essential oil utilized as a natural corrosion preventer for Carbon steel in 1 M hydrochloric acid solution was examined utilizing electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) methods, UV-visible spectra and scanning electron microscopy (SEM)/(EDS). The results of these examinations demonstrated that Mentha piperita essential oil was a significant inhibitor. The inhibition efficacy (%IE) improved with rising essential oil of Mentha piperita leaves concentration and decreasing temperature. At 100 ppm, the extract showed exceptional inhibitory action, with an efficiency of 89.6% at 303 K. According to polarization curves, the Mentha piperita essential oil functions as a mixed inhibitor, it was clarified by the carbon steel surface absorbing Mentha piperita essential oil. The adsorption process follows the Langmuir isotherm. Studies on electrochemical impedance spectroscopy revealed a single capacitive loop, demonstrating the procedure of a charge transfer was responsible for controlling the corrosion reaction. The kinetic activation and adsorption process' thermodynamic characteristics were also estimated and explained.

In the present work, N-(imidazol-2-ylcarbamothioyl)benzamide was developed and employed as an ionophore for preparing three kinds of membrane chromium(III) selective electrode including electrode with liquid internal electrolyte (LIE), solid-state electrode (SSE) and coated wire electrode (CWE). Optimal membrane composition was determined to be 2% sodium tetraphenylborate, 58% dibutyl phthalate, 10% ionophore, and 30% polyvinyl chloride, resulting in Nernstian slope behavior. Linear concentration range was 1×10-3-7×10-6 mol L-1, 1×10-3-3×10-7 mol L-1, and 7×10-3-3×10-9 mol L-1 of chromium(III) with Nernstian slope 20.76, 21.79 and 19.05 mV/decade for LIE, CWE and SSE, respectively. An improvement was note in detection limit for SSE (3×10-9 M) and CWE (2×10-7 M) in comparison with LIE (7×10-6 M). Response times were approximately 5 seconds for LIE and CWE, and 4-6 seconds for SSE. The applicable pH range for the electrodes was 3.0-5.0. SSE and CWE demonstrated longer lifetimes of about 13 and 12 weeks, respectively, compared to LIE (11 weeks). These electrodes were utilized as indicator electrodes in the chromium(III) potentiometric titration with ethylenediaminetetraacetic acid.

Electrodeposition of Zinc-Iron alloy has been used to improve the corrosion resistance of mild steel. This alloy plating was successfully coated on mild steel using the electrodeposition technique. Under varied deposition conditions, the zinc-iron alloy films onto the steel plate were examined. The purpose of this study is to describe the corrosion characteristics of the coated sample in 3.5% NaCl for the application of novel, sacrificial coatings for the defence of steel structures. It has been thoroughly examined how plating variables including bath composition, pH, and current density affect the composition, morphology; and corrosion properties of the coatings were discussed. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) are used to analyze the morphological characteristics and phase structure of the coatings. The surface roughness of the coating was measured by Atomic Force Microscopy (AFM). The Vickers indenter was employed to measure the microhardness of the coated sample. The corrosion resistance of Zn-Fe alloy coatings was assessed using electrochemical impedance spectroscopy (EIS) and polarization techniques at different current densities. The new low-cost Zn-Fe alloy coating was used for automobile applications.

A new all-solid-state ion selective electrode (ASS-ISE) was developed for the determination of thulium trivalent cation. The potentiometric sensor was made by depositing a thin PVC membrane containing N՛-[(2-hydroxyphenyl)methylidene]-2-furohydrazide (L) as a selectophore on a conducting solid-state electrode. The solid-state electrode was a thin copper wire coated by a mixture of multi-walled carbon nanotubes (MWCNTs) and an epoxy resin. The optimal composition of the PVC membrane was 25%wt. of PVC powder, 68% wt. of benzyl acetate, 2% wt. of sodium tetraphenyl borate (NaTPB)), and 5% wt. of L. The sensor showed good selectivity for Tm3+ ion with a Nernstian calibration plot slope of 19.6±0.4 mV/decade in Tm3+ ion solutions with concentrations ranging from 1.0×10-8 M to 1.0×10-3 M, and its limit of detection was as low as 6.3×10-9 M. The proposed sensor was able to detect Tm3+ cations in the wastewater matrix. 

Soil contamination presents a significant hazard to both ecosystems and human well-being. Therefore, there is a need for cost-effective and environmentally friendly approaches to decontaminate polluted soils. Soil remediation involves the treatment of contaminated land to enhance soil quality, safeguarding public health and the ecosystem. Among the promising technologies for remediating soils contaminated with various substances, including inorganic, organic, and mixed contaminants, is electrochemical remediation. Electroremediation (ER) is an in-situ method that employs low direct electric current among electrodes fixed in contaminated soils to create an electric field. This review paper examines the advancements made in recent years in electrochemical remediation as an effective method for decontaminating polluted soil. The discussion begins by exploring electrochemical remediation, followed by the classification of contamination types in soil. The focus then shifts to the application of electrochemical treatment methods for removing heavy metals and organic contaminants from the soil. Additionally, the paper highlights recent progress in the exploration of integrating electrochemical treatment with other remediation techniques, such as phytoremediation and bioremediation.